1. Field of the Invention
The present invention generally relates to a connector assembly comprising male and female connectors adapted to be connected together and, more particularly, to a lock mechanism used in the connector assembly to facilitate a connection between the male and female connectors and also to lock one of the male and female connectors in a condition firmly connected with the other of the male and female connectors.
2. Description of the Prior Art
In an automobile, for example, electric wires used to distribute electric power among numerous electrically operated devices are bound together into harnesses. Those electric wires bound together into the harnesses are generally known as wiring harnesses and are generally marked by means of colors for identification purpose. The electric wires forming the wiring harness may lead out from an electrically operated device and terminate in a terminal connector for connection with a different electrically operated device through another similar wiring harness having a mating terminal connector at its opposite ends.
In the case of harness-to-harness connection, it is a general practice to employ a plug-in connector assembly comprising a plug connector including a number of terminal pins and a socket connector including a corresponding number of terminal sockets for receiving the terminal pins. To connect the plug-in and socket connectors together to establish electric circuits between the electric wires terminating in the plug connector and the electric wires terminating in the socket connector, a pushing force must be applied to one of the connectors, while the other of the connectors is held stationary, so that such one of the connectors can be urged to the other of the connectors with the terminal pins inserted into the associated terminal sockets.
It has hitherto been experienced that the greater the number of the terminal pins, the larger is the pushing force required to complete the connection.
In order to minimize the pushing force required to accomplish the firm connection between the plug and socket connectors, the use has been made of a lever mechanism designed to facilitate a draw of one of the connectors close towards the other of the connector and also to lock the connectors in a connected position, such as disclosed in, for example, the Japanese Laid-open Patent Publication No. 55-80282 published Jun. 17, 1980, and the Japanese Laid-open Patent Publication No. 2-56875 published Feb. 26, 1990.
The lever mechanism disclosed in the first mentioned publication comprises a generally tubular operating member comprised of top and bottom walls and a pair of opposite side walls and mounted on one of the plug and socket connectors, for example, the plug connector. Each of the side walls of the operating member is formed with a pair of guide grooves cooperable with guide pins formed on each side wall of the socket connector, said guide pins being so defined and so positioned that, when the plug and socket connectors are aligned with each other in readiness for insertion of one of the connectors into the other of the connectors, the guide pins can be received in the associated guide grooves.
The guide grooves defined in the operating member are so defined and so shaped that, when the operating member is pushed to displace towards a locked position in a direction transverse to the direction of insertion of one of the plug and socket connectors into the other of the plug and socket connectors after the plug and socket connectors are aligned with each other with the guide pins received in the associated guide grooves, the guide pins can be guided deep into the associated guide grooves while the socket connector is forcibly drawn close towards the plug connector and, at the time of completion of the movement of the operating member to the locked position, the plug and socket connectors can be connected together with the terminal pins firmly inserted into the respective terminal sockets.
In this prior art lever mechanism, each of the guide grooves defined in the operating member is comprised of a straight groove portion extending generally parallel to the direction of insertion of the plug connector into the socket connector and a slant groove portion continued from the straight groove portion and extending generally diagonally relative to the direction of movement of the operating member which is transverse to the direction of insertion.
The above discussed prior art lever mechanism has been found having the following problems. In the first place, although the force necessary to push the operating member towards the locked position thereby to accomplish the complete insertion of one of the plug and socket connectors into the other of the plug and socket connectors is smaller than the force necessary to push one of the plug and socket connectors relative to the other of the plug and socket connector to accomplish the same effect, the force necessary to push the operating member is not always uniform throughout the entire stroke of movement of the operating member from a release position to the locked position and a progressively increasing force is required as one of the plug and socket connectors is drawn closer towards the other of the plug and socket connectors.
In addition, once the operating member has been moved to the locked position, the bottom wall of the operating member remains projecting a distance outwardly from a bottom of the connector assembly. This is because the top and bottom walls of the operating member movable from the release position towards the locked position must be spaced a distance greater than the thickness of the connector assembly so that the top wall of the operating member spaced a distance outwardly from the top of the connector assembly prior to the movement of the operating member from the release position towards the locked position can be held in contact with the top of the connector assembly after the operating member has been moved to the locked position. Therefore, in the event that an external force acts on the bottom wall of the operating member by some reason, the operating member may be moved from the locked position towards the release position allowing one of the plug and socket connectors to be accidentally separated away from the other of the plug and socket connectors.
The second mentioned publication, that is, the JP Laid-open Patent Publication No. 2-56875, discloses the use of the lever mechanism employed in the form of a generally U-shaped lock handle supported for pivotal movement between release and locked positions spaced angularly from each other about an axis of rotation of the lock handle. The generally U-shaped lock handle includes a handle bar and a pair of generally L-shaped arms connected at one ends with opposite ends of the handle bar. This U-shaped lock handle is mounted on, for example, the plug connector having its opposite side walls provided with coaxial bearing pins onto which respective free ends of the arms of the lock handle are rotatably mounted. The lock handle is pivotable between the release position, in which the arms of the lock handle extend diagonally upwardly in a direction opposite to the socket connector with the handle bar positioned spaced a distance upwardly from a top of the plug connector, and the locked position in which the arms of the lock handle extend generally parallel to the direction of insertion of the plug connector into the socket connector with the handle bar resting on the top of the plug connector.
The plug connector has its opposite side walls formed with respective recesses for receiving therein associated guide pins formed on corresponding side walls of the socket connector. In order for the guide pins on the side walls of the socket connector to be engaged in the respective recesses in the side walls of the plug connector to accomplish the firm connection between the plug and socket connectors, curved cam flanges are formed on the respective free ends of the arms of the lock handle. These cam flanges are so shaped and so configured that, when the lock handle is pivoted from the release position towards the locked position after the plug and socket connectors have been mated with each other, leading ends of the respective cam flanges with respect to the direction of angular movement of the lock handle towards the locked position enter behind the guide pins so as to encompass the associated guide pins and the continued angular movement of the lock handle can cause the cam flanges to draw the associated guide pins close towards the plug connector so as to enter the respective recesses in the side walls of the plug connector.
The lever mechanism disclosed in the second mentioned publication also comprises a lock means for locking the lock handle in the locked position, which means comprises a pair of detent projections protruding outwardly from the respective side wall of the plug connector and detent holes defined in the respective arms of the lock handle. When the lock handle is pivoted to the locked position, the detent projections engage in the associated detent holes to lock the lock handle in the locked position.
While the plug-in connector assembly according to the second mentioned publication operates satisfactorily, it requires a visual inspection to ascertain whether or not the lock handle has been moved to the locked position and, hence, whether or not the plug terminals have been electrically completely connected with the socket terminals.